1. Field of the Invention
The present invention relates to a mounting assembly and a mounting method for an electronic component, and more particularly to a mounting assembly and a mounting method for disposing an integrated circuit, an LSI, a chip resistor or a chip capacitor on a printed board.
2. Description of the Prior Art
In electronic devices such as calculators and personal computers, electrical circuits are arranged by disposing IC (integrated circuits), LSI (Large-Scale Integration), resistors and capacitors on a printed board on which wiring patterns are formed.
Base materials such as flexible plastic sheet, hard paper-phenol resin board or glass-epoxy resin board on which are formed conducting patterns of conductive material, or film carrier tape are used as printed boards.
Various components are used as electronic components such as integrated circuits, LSI and diodes on which several to a large number of leads are arranged around the perimeter of the component body, or items such as chip resistors and chip capacitors which do not have any leads.
In these types of conventional mounting assemblies, however, the electrodes (or leads) of an electronic component were fixed directly to the wiring patterns on the printed board by solder or a conductive adhesive.
Such conventional arrangements suffered from several problems. Alignment of the positions of the electrodes on the electronic component and on the printed board was difficult, and accurate connection required considerable effort. Connecting the electronic component to the printed board, connecting the electrodes of the electronic component to each other, and connecting the electrodes of the printed board to each other required separate processes, resulting in a large number of steps. Concentrated stresses arose easily in the connecting portions between electrodes, leading to the peeling off of electrodes. When the connecting section between the electronic component and the printed board was thick, a long time was required to heat it, impeding the efficiency of connecting operations.
Furthermore, in such conventional arrangements, the thickness of the electronic component formed protrusions on the printed board, so that such arrangements could not be used as thin mounting assemblies.
Moreover, in the case of an electronic component such as an LSI which has electrodes around its perimeter, the LSI body is inserted into an opening formed in the printed board, and the peripheral electrodes are connected by overlaying them on the printed board. Such peripheral electrodes have considerable thickness which forms protrusions on the printed board. Accordingly, with this arrangement, it is difficult to form a thin mounting assembly.